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DEVELOPMENT AND PRODUCTION OF SPECIAL LIP SEALS

1. Our works on modernization of sealing units of bearing supports are directly connected with development and delivery of self lip seals for various functional purposes as for application in the modernized sealing units, and so for any other units of the existing and new equipment, including import.

The main reason of this developments which we began in the 1980´s, was the impossibility of creation of modern reliable sealing units, especially for supports with large-size bearings, using only available standard lip seals (generally the radial shaft seals in accordance with ГОСТ 8752-79 and some other branch standards).

2. First of all it was developed the range of V-ring seals (their analogs were already widely applied by foreign firms).

The characteristic feature of these seals, which is very valuable for their application, is lack of need of rigid demands to execution accuracy of the connecting dimensions of sealing unit and possibility of ensuring sealing effect even at considerable not coaxial, misalignment and axial displacements of details (shaft and housing) of rotary connection.

On Figure 1 the main dimensions of units with V-ring seals for various sizes of cross sections from V0 to V5 are shown.

Fig. 1

V-ring seals product now for shaft seating diameters dг from 60 to 1900 mm.

3. During development of various sealing units (information materials on many of them are placed at this site) were designed and put on production and some another non reinforcement lip seals that do not have domestic or foreign analogs. Most widely applied of this seals are described below.

3.1. The axial double side «flouting» seals (ТПД type), shown on Figure 2, are established on shaft with a tightness. They provide possibility of reliable sealing for rotating connection at almost unlimited axial shift of a covering detail (housing) concerning a shaft. Counter faces of a covering detail provide seal replacement along shaft diameter

Fig. 2.

There are various executions (from TПД0 to TПД3 type) in accordance with cross sections dimensions and seal sizes for shaft diameters from 75 to 560 mm.

3.2. Radial seals with an external lip (РН type) presented at Figure 3, as well as other unreinforced seals, are fixed in shaft seating’s at the expense of a tightness of seals. They are intended, generally for protection of bearing units against external pollutions and keep efficiency at considerable not coaxial ties, wears and axial shifts of sealing units details.

Fig. 3.

There are various executions (from PH0 to PH3 type) in accordance of cross sections dimensions and seal sizes for housing bore diameters from 70 to 1950 mm.

3.3. Seals with radial external and nongliding axial lips (РНСТ type), were developed specially for external steps of the modernized sealing units for oil film bearings. Apparently from Figure 4, seal «РНСТ» are fixed on covered (connected with roll) details of rotating connection for couples not only a tightness, together with at the expense of a clip of axial lips between details on the roll at their assembly.

Fig. 4.

Thus axial (nongliding) lips protect from pollution from the outside motionless connections of the details fixed on the roll, and the radial external lip sliding on cylindrical bore Dр, forms the first step of protection of rotating connection from environment influences (water, scale and so forth).

Seals РНСТ1, РНСТ2 and РНСТ3 tips were developed and applied to the modernized sealing units respectively from «ПЖT 140» to «ПЖT 300», from «ПЖT 320» to «ПЖT 650» and from «ПЖT 800» to «ПЖT 1800».

4. Despite existence of a wide range of the radial reinforced seals for shafts (in accordance with ГОСТ 8752-79 and on some branch standards) it became clear that this range appears often insufficient, especially in the areas of averages and the large sizes. It appeared especially notable in need to choose seals of for the import equipment sealing units. Besides practically there was no specialized production of seals for shaft diameters over 500 mm.

In this regard are developed and product reinforced radial seals with demountable reinforcement rings (designated «РСК t-dB»), where, as is shown in Figure 5. Here t – width of a seal, and dB – diameter of a shaft are issued.

Distinctive feature of these seals is that reinforcement rings are demountable, and the replaceable seals put on reinforcement rings before installation in bore D of housings.

Fig. 5.

Seals of «РСК» type are produced for shaft diametersfrom 60 to 1300 mm, and if necessary, for bigger diameters too. Thus steps of a range row are, generally 5 mm for <620 mm and 10 mm for > 620 мм.

External diameters of the assembled reinforced seals: D = dв + ΔD.

The range of this seals provides choice possibility for almost any units with the known standard or normalized domestic and foreign seals interchangeable with them «РСК» seals. At the same time, thanks to possibility of use of replaceable lip seals of each size with a number of different reinforcement rings, seals of «РСК» type have much more frequent and in need of any, the step of diameters of shafts, and also allows to make seals for any units of the import equipment.

Thanks to big radial deformation of seal lips in assembled unit (from Δ = 2,1 mm for «РСК12-dB» to 6,0 mm for «РСК40-dB») without using the garter springs or any other elements for tightening seal lips to a shaft the good sealing effect is reached, including at distortions of shafts.

In recent years use the increasing demand for radial seals with a rubber-fabric reinforcing rimbut without steel shell or ring (designated РБ dв × D×t, Figure 6)

Fig. 6.

Sealing function is realized, as well as in РСК type seals, at the expense of own elasticity of lips, without using the garter springs. The accuracy and the rigidity of seal rims , sufficient for their reliable fixing in bore of housing details, are provided thanks to reinforcing of seal body by a rubber-fabric material.

The main feature of these seals attractive to exploitation is possibility of their installation in the closed bore (without displacing of lateral flanges) that accelerates processes of installation or replacement of seals.

All mentioned above and also many other types of special seals are presented in the SEG 11/R catalog placed on this site.

5. We develop and organize production of the most various special lip seals. It is characteristic in this case developed and delivered by us on Samara Bearing Factory (Samara, Russia) РБ 361М seals specially developed for installation in tapered roller bearing 6-77968ХМ3 shown on Figure 7.

Fig. 7.

In these seals all their body rigid part is executed by the rubber-fabric material. Bearings 6-77968 ХМЗ with our built-in seals successfully work on a cold strip mill at Novolipetsk Metallurgical Works (Lipetsk, Russia).